Download the JS file, download the file to the browser sandbox and report an error

the code is as follows:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <input name="download" id="download" />
    <button type="button" onclick="down()"></button>
</body>
    <script>
        function down() {
            window.webkitRequestFileSystem(Window.TEMPORARY,1024*1024,function(fs) {
                var fileEntry = fs.root.getFile("Test.txt",{create: true});
                var fileWriter = fileEntry.createWriter();
                fileWriter.seek(10);
                var blob = new Blob(["hello,the world"]);
                fileWriter.write(blob);
                console.log("Successfuly")
            },(err) => {
                console.log(err);
            });
        }

    </script>
</html>

browser error:

DOMException: It was determined that certain files are unsafe for access within a Web application, or that too many calls are being made on file resources.
Mar.01,2021

as far as I understand it, browsers do not allow js to manipulate local files directly, which is not safe. If you can access local files directly, what about the security of computing?

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b31919-2b520.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b31919-2b520.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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